1. Field of the Invention
The present invention relates to an imaging apparatus, and more particularly, to an imaging apparatus which allows an image sensor to adhere to and to be fixed to a fixing member.
2. Description of the Related Art
An imaging apparatus, such as a digital camera, captures an image by converting an object image into an electric signal. The imaging apparatus receives a shooting light flux by an image sensor, converts a photoelectric conversion signal output from the image sensor into image data, and records the image data in a recording medium such as a memory card. A charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) sensor is used as the image sensor.
Such an imaging apparatus needs to keep an image sensor at a high level of reliability, while accurately maintaining a relative positional relation among a plurality of optical components. In the case of a digital single-lens reflex camera using a recent large-sized image sensor, a relative positional relation between an image sensor and an optical viewfinder and a positional accuracy in a shooting focus direction are required.
For example, Japanese Patent Application Laid-Open No. 2007-227673 discuses technique in which an image sensor adheres to and is fixed to other components or a substrate to form an imaging unit, and the imaging unit is held with respect to an imaging apparatus. According to an adhering method discussed in Japanese Patent Application Laid-Open No. 2007-227673, an adhesion-purpose opening is disposed in an image sensor fixing member within a range of projecting the image sensor. The image sensor is fixed by pouring an adhesive into the opening of the image sensor fixing member.
Also, Japanese Patent Application No. 2006-203624 discuses an adhering method in which openings of an image sensor fixing member are disposed substantially uniformly within a range of projecting an image sensor. Therefore, since adhesion-purpose openings are disposed substantially uniformly, strength enough to withstand a drop impact of a camera can be obtained.
However, in the imaging unit discussed in Japanese Patent Application No. 2007-227673, the adhesion-purpose opening is provided at one position corresponding to a central location of the image sensor, and the cross-sectional shape of the opening is straight in a thickness direction. Therefore, sufficient adhesion strength is difficult to be obtained. It is described therein that the adhesion strength is about 10 times the weight of the imaging unit.
Further, in the imaging unit discussed in Japanese Patent Application No. 2006-203624, since the adhesion-purpose openings are disposed substantially uniformly on the backside of the image sensor, a sufficient strength can be obtained. However, in the case that the openings adhere to and are fixed to the back side of the image sensor over a wide range, when the image sensor is placed under high temperature or low temperature, since the image sensor and the image sensor fixing member are different members, the image sensor is greatly deformed by the influence of a thermal strain caused by a difference in linear expansion coefficient.